Best birth controls!!

Just had my son July 13. Had my follow up appointment at 7weeks which was Yesterday. I talked to her and told her I was interested in the nexplanon implant and she was like she recommends the iud because nexplanon makes you gain weight and you’ll have irregular bledding and the only thing about the iud is that “it hurts”. I’m stuck in between the two still because she mentioned I have to continuously check to make sure I can still feel the strings and also look in the toilet to make sure it hasn’t fell out and I feel like that’s ridiculous that I have to keep checking down there. And nexplanon I don’t want to gaining weight shit I’m already fat enough 🤣 Any ideas on the best one with LEAST side effects.